Category: syscall emulation

Wow this was without a doubt one of the more confusing things I’ve ever done.

So here is the problem. I want to delete some files from an IMD disk image, and then copy some new ones in. Easy right? .. maybe.

Ok first up the easiest tool I’ve found to manipulate CP/M disk images is cpmtools. Even better their pre-compiled binary is for Win32, so I’ll run it with Wine on OS X. which works fine. Although there is one slight problem, cpmtools doesn’t read the IMD disk format. So you will have to download imd118.zip from a backup of the late author’s computer.

Now using IMD you need to convert the OS disk into a ‘raw’ or ‘binary’ file. Naturally IMD is a MS-DOS program so firing up DOSBox, I ran:

Uncompressing, so easy!

IMDU CPM68K12.IMD CPM.RAW /B

And a few seconds later I had my raw file. Now the next thing was to manipulate the image in cpmtools. cpmtools has a database of disk drive types, and naturally there is no definition for the SAGE2. However thanks to a friend of mine (hi Lorenzo!) I took at look at 22disk, and found their demo version did in-fact have a definition for the SAGE:

So I tidy up the image, and copy it back to the IMD program for compressing. And this was, without a doubt the most difficult to figure out, until after a bunch of searching, and Lorenzo once more again pointed me in the direction of bin2imd

not intuitive!

So yeah.

BIN2IMD X.RAW X.IMD DM=2 N=80 SS=512 SM=1-8 /2

And the best part is that it worked! So now I was able to transfer over a binary version of com.68k, com2.68k, along with Zork, and fire it up!

8080 Zork on 68k CP/M

Unfortunately the interpreter doesn’t work right. It could be the disk transfers fault, maybe the SIMH SAGE emulator, or even the 8080 emulator. But it worked this far.

Oh well, I was able to build a simple hello world type program, but anything that hopes to pull data off the drive won’t work. If anyone thinks they can do better my archive of all the bits is here (48MB), and the ‘runnable’ version is here .. hi is about as much fun as it’ll get.

I know that there is some people out there that seem to be all into Xenix, and old binaries… So I thought I’d share this little gem I found before I head out for the day… I came across this post, talking about how ibcs2 has fallen apart in the latest version of NetBSD. But the gem in there is that version 4.0.1 works perfectly fine!

So I copied in the old gcc, filled in some bits and….

Qemu 0.14.0 NetBSD 4.0.1 running Xenix gcc

It works!

Robots is so perfect you’d never know!

Qemu 0.14.0 NetBSD 4.0.1 running robots

And it runs Xenix Dungeon/Zork without missing a beat!

Qemu 0.14.0 NetBSD 4.0.1 running dungeon

So this may be yet another avenue for some people… I’d suspect that you could even build the 32v userland under the Xenix tools…? Since all the default stuff is keyed to licensing, but you could roll your own Unix v7 32bit userland which basically is Xenix and go from there…. Maybe even some of the OpenSolaris SYSVR4 stuff as well but that sounds too ambitious!

Since the last time I reviewed it, the MS-DOS Player, by Takeda Toshiya has come a long way!. He’s fleshed out more of the MS-DOS emulation, and updated the CPU core.

I’ve now been able to run the Microsoft C 5.1 compiler under Windows 7:

MS-DOS Player running Microsoft C 5.1

Check it out!

The MS-DOS Player is similar in nature to DOSBox, except that it’s not interactive, but rather built for CLI batch based operation. The MS-DOS Player seems to have some 80286 capabilities, but it’s BIOS/DOS emulation doesn’t seem to have the protected mode interface to allow dos extenders to work.

It’s certainly great for people that still have ANCIENT cli based programs that you’d want to call & capture their output. This is a life saver for some of us that still rely on dbaseIII & some ancient i8085 micro controller.

I don’t know how I didn’t find this earlier, and how it’s been overlooked for so long….

But this incredible program, LINE, will run statically linked Linux ELF binaries on Windows.

Yes, you read that right, this user mode program will load an ELF exe, and run it under a software debugger with no need for device drivers, and intercept all the sycalls (ie int 0x80’s) through the cygwin1.dll, giving you a POSX/Command line linux experience.

It does come bundled with various hello programs, and a few things on testing forks… But the real magic for me was being able to grab a static version of dungeon, and running it on both Windows 7 x64, and emulated NT 4.0.

And it works!

I’ve put my copy of dungeon, along with a copy of cygwin1.dll that works with the LINE package here for anyone interested.

I’m just amazed at the size, and simplicity of the whole thing…..

In the documentation there is even mentions of NSO (Native shared objects?), and dynamic linking…

Psim is one of those great peices of software that has been long sice forgotten. In every copy of GDB since 4.14 it has been sitting there dormant. What is it? Well it’ll emulate various PowerPC systems to some degree (GXemul & Qemu are better now) but what is cool is the ‘run’ program. Simply put, any system that can run GDB can run powerpc NetBSD statically linked EXE’s! Now isn’t that exciting!

Now I know you’ll want to build your own copy of the ‘run’ program, and then setup a cross compile enviroment so that you, to can produce NetBSD PowerPC executables. I’m assuming that you are not on a PowerPC running NetBSD, since this whole excersize would be… redundant.

For this example I’m using OpenBSD 4.0 on the i386. You will need a real unixy envioment for this. MinGW isn’t good enough, cygwin however is. BSD/Linux will work too.

Ok first let’s start with building the run program. I’m going to download my GDB from ftp://ftp.gnu.org/ .

Gdb 5.3

Unpack it somewhere, and then run the following commadn to configure GDB.

You will need to replace or update the sim/ppc/emul_netbsd.c program to include system calls up to 300, and make sure that 279 is setup to do_fstat. Otherwise you will be unable to run any programs. This is also a good excersize to see how libraries interact with the simulator so you can add your own native interfaces, for things like OpenGL, SDL….

Now we are ready to build it.. You could use -O0 in your CFLAGS to build it quicker, but it will result in a slower run times.. If you have issues with this you will want to use those flags so it doesnt take forever to be building this thing. Otherwise a simple ‘make;make install’ will suffice.

Next up is binutils. I’m using version 2.17

Binutils 2.17

Again download and unpack this somewhere (/usr/src?) Then run the following to configure your binutils

./configure --target=powerpc-unknown-netbsd --prefix=/usr/local/psim

Since execution time here isn’t as critical as the emulator, and I want to hurry it along I’m going to use the following command to build & install:

make CFLAGS=’-O0 -pipe’ ;make install

On OpenBSD 4.1 the install fails, and I had to manually copy the binutils applications into /usr/local/psim/powerpc-unknown-netbsd-bin